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Red Sox first baseman Adrian Gonzalez thinks a sweep of today's doubleheader with the Yankees will just about assure his club a trip to the postseason.

If only it were that simple.

Thanks to an epic September slide, Boston may very well need to take both games from New York on Sunday, but that is easier said than done, especially considering it must face the streaking Ivan Nova in the nightcap.

After Friday's opener of this three-game set was rained out, the Red Sox sent ace Jon Lester to the hill last night hoping to turn things around. However, Lester failed to make it out of the third inning, giving up eight runs before his exit as Boston dropped a 9-1 decision.

It was the sixth loss for the Red Sox in their last seven games and they fell to 5-17 in the month of September. They led the American League East by 1 1/2 games entering the month, but now hold just a 1 1/2-game edge over the Rays for the wild card position. A victory by Tampa Bay today and a loss in both games by Boston would even the two clubs in the wild card race.

"We all want to win. It's up to us to go do it," said Red Sox manager Terry Francona. "We know what's in front of us, we just have to play better."

The Angels are also within reach of the Red Sox for the final playoff spot after Boston lost for the first time in seven games this season at Yankee Stadium. New York improved to just 5-11 in the 2011 season series, but the victory and Detroit's loss on Saturday night clinched home-field advantage for the Yankees through the AL Championship Series.

The Red Sox hope to get another crack at the Yankees in October, but need to turn things around quick. It wasn't that long ago that they swept a doubleheader with the Yanks, however, doing so in the Bronx on Sept. 17, 2006.

"If we come out tomorrow and win the two games, we'll pretty much be a lock to be in the playoffs," said Gonzalez. "Things can turn in a matter of, what, 15 hours?"

Derek Jeter hit a three-run homer to cap a six-run second inning and Jesus Montero delivered a solo homer and drove in four runs for New York, which would love to be the reason Boston fails to make it to the playoffs.

Nova could deliver a devastating blow to those chances in the nightcap if A.J. Burnett can take care of business in the first game. He is undefeated this month even though he has pitched to a 5.06 earned run average in four starts. That is still an improvement over a tough August in which the right- hander had an 11.91 ERA in five starts.

Burnett, 34, is 10-11 with a 5.28 ERA in 31 starts this year, including an 0-1 mark and 7.36 ERA in two games versus Boston.

Nova, meanwhile, won his 12th straight decision on Tuesday with a victory over the Rays. He tossed 7 2/3 scoreless innings, working around six hits and three walks. He is the first New York rookie to win 12 in a row since Atley Donald in 1939, with his last loss coming on June 3.

"The distance and the no runs is what I like the most," said New York manager Joe Girardi about Nova. "He was outstanding and did a lot of things right out there."

The 24-year-old righty is 16-4 with a 3.62 ERA on the season and likely won't resemble the same pitcher that Boston faced back on April 9, when it got to Nova for four runs on seven hits and three walks over 4 1/3 innings.

Set to take the hill for Boston in the first game, Tim Wakefield will make only his second start of the season versus the Yankees and first since June 8, when he gave up five runs on five hits and three walks in 5 1/3 innings of a victory in the Bronx. Tonight will mark the 45-year-old's 58th career meeting and 36th start versus the franchise.

Wakefield notched the 200th win of his career on Sept. 13 with a victory over the Blue Jays, but took a loss to the Rays on Sunday after being charged with six runs -- two earned -- on six hits over five innings. He fell to 7-7 with a 5.08 ERA in 32 games this year, including 22 starts.

"He just never got into a real good rhythm. He threw some real good knuckleballs. He just seemed to be working out of the stretch a lot," Francona said of the right-hander.

John Lackey draws the tougher assignment by going against Nova in the second game. The right-hander hasn't won since Aug. 23 and lasted only 4 1/3 innings versus Baltimore on Monday. He was charged with eight runs on 11 hits and failed to record a decision despite Boston winning the game, 18-9.

"I'm glad we won, obviously, but I'm pretty frustrated," said Lackey, who is 12-12 with a 6.49 ERA on the season.

The 32-year-old holds a winning record in three starts against New York this year (2-1) despite a 6.50 ERA.

The Yankees could turn from foe to friend for the Red Sox on Monday as they open a three-game series with the Rays, while Boston visits Baltimore for its final three games of the season.